I have the same problem with my enlarger, an Omega B66. .... it's difficult to ever get the same reading twice.
Exactly.... hence my original question of what is "good enough?" I just discovered, putting a tool on the lens board itself actually causes enough of off center weight that the bubble moves off center by just a little.
I got it to a point where projected image is square and the image at 20x20 or so is sharp to my unaided eyes. I'm going to stop right here.
In the evolution of equipment there have been some good and bad designs. Some got lucky with a buy and it worked perfectly, others got poor designs and they always had troubles. It's like cars, some are good and a few are not. My Beseler 45 has so many struts and racks and pinions to allow the head to rise and fall at an angle that it's really odd that it was a viable option for the design. The Durst enlargers have a massive post and the head moves up and down in a straight line. The lack of precision caused by years of mechanical movement and wear makes the Beseler a nightmare to align and keep aligned. When you put a lens that was made to high optical specifications on an erector set type enlarger instead of an optical bench there is going to be difficulty in alignment.
Everytime I find a film or paper that I like, they discontinue it. - Paul Strand - Aperture monograph on Strand
Not if the neg to lens is out of alignment. Stopping lens down will improve it to a point but you'll never get it really sharp if lens is not perpendicular to neg.
Most good enlargers allow the lens to be shifted & tilted from the perpendicular, and the head to be tilted to allow some movements to correct verticals etc. This is only ever sideways though..
I have a high contrast reference test plate that came boxed with a Johnsons V45 enlarger in the 70's, this allows accurate alignment of an LF (5x4) head and lens.
My point was though that deliberately going off alignment, it doesn't matter whether lens to negative or lens to paper, by even quite a significant amount can be controlled by careful focus & the enlarger lens DOF stopped down even a couple of stops.
Normally I'd use the enlarger tilts & shifts but it was a panoramic negative which wouldn't allow fitting in the enlarger front to back (only side to side).
what would in notice in printing with the v35 if it is not aligned?
Parts of the negative will be be focus in the print, while other parts will not.
Shapes in the image will be skewed and angles in the image which ought to be square, won't be.
You can check for this using the test that Mike Wilde suggests in post #5 of this thread:
Originally Posted by Mike Wilde
A thumbnail alignment tool -that I use for checking from time to time that important things are still working and in alignment.
DIY - take a black film leader of the format in question, and put it in the neg carrier with the emulsion side up. Scratch the outline of the neg carrier with a pin/needle. Take the neg out, and draw diagonals from corner to corner.
Put the film back into the carrier, and mount the carrier in the easel. Focus on the neg at the desired head height under test, with the lens cone, lens etc. under consideration. The diagonal lines should be sharp from end to end, and the distances of the opposing sides should measure the same.
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2